Stunning: Damaging or Protective to the Myocardium?

Ferrari, Roberto; Visioli, O

doi:10.1007/978-1-4613-1517-9_12

Cited by 1 publication

(4 citation statements)

References 49 publications

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“…If the hibernating myocytes are ischemic, the old and often-questioned concept of "chronic ischemia" should, indeed, be reconsidered. This level of underperfusion was unable to restore normal interstitial pH and contractility, but did restore normal aerobic metabolism, as demonstrated by the absence of lactate, purine, and CPK release; the maintenance of mitochondrial function and of tissue stores of ATP and CP; and full recovery of contraction on reperfusion after as long as 4-6 hours of low-flow ischemia [26]. This short period of ischemia caused, as expected, a rapid drop in interstitial pH, quiescence, and the release of lactate [26][27][28].…”

Section: Determinants Of Hibernating Myocardiummentioning

confidence: 96%

“…We tried to answer these questions by monitoring the metabolic and functional changes occurring in isolated and perfused rabbit hearts first subjected to a severe reduction of coronary flow from 22 to 0.5 ml/min for 10 minutes [26]. If the hibernating myocytes are ischemic, the old and often-questioned concept of "chronic ischemia" should, indeed, be reconsidered.…”

Section: Determinants Of Hibernating Myocardiummentioning

confidence: 99%

“…Systolic shortening and diastolic calcium extrusion requires 75-80% of ATP consumption [26]. Intracellular acidosis has an indirect protective effect and might contribute, together with residual coronary flow, to the maintenance of viability of hibernating myocytes.…”

Section: Determinants Of Hibernating Myocardiummentioning

confidence: 99%

“…Intracellular acidosis has an indirect protective effect and might contribute, together with residual coronary flow, to the maintenance of viability of hibernating myocytes. This concept will explain why the hibernating myocardium does not produce lactate (a typical marker of ischemia) [10,25,26] and shows indirect signs of metabolic activity [21,30]. Acidosis, by lowering the contractile state of myocytes, reduces oxygen demand, allowing maintenance of viability in the setting of limited oxygen supply [29].…”

Section: Determinants Of Hibernating Myocardiummentioning

confidence: 99%

See 3 more Smart Citations

Hibernating myocardium in patients with coronary artery disease: Identification and clinical importance

Ferrari

Canna

Giubbini

et al. 1992

Cardiovasc Drug Ther

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The term hibernating myocardium describes a particular outcome of myocardial ischemia in which myocytes show a chronically depressed contractile ability but remain viable. Revascularization of hibernating tissue causes a recovery of mechanical function that correlates with long-term survival. Therefore it is important clinically to distinguish hibernating from infarcted myocardium, since asynergies due to hibernation will improve on reperfusion, whilst those due to infarct will not. One suggested technique to identify hibernating myocardium is to stimulate the myocytes acutely, but briefly, by administration of inotropic agents while monitoring contractile function by echocardiography. We report our experience on the use of low dosages of dobutamine. Myocardial viability was validated by measuring the recovery in contraction of the akinetic areas after coronary artery bypass surgery by means of intraoperative epicardial echocardiography. The test has a sensitivity of 93% and a specificity of 78%. It is useful for identification of viable myocardium and also for quantification of intraoperative risk in individual patients. Limitations of this test are related to the presence of downregulation of beta receptors and to the impossibility of differentiating hibernating from stunned myocardium. Another useful technique of identifying hibernating myocardium is the use of radionuclear markers for viability. In our experience the two most important tests are (1) rest-redistribution imaging of thallium 201 (which has a high sensitivity of 93% but a low specificity of 44%) and (2) 99mTc-Sestamibi imaging, which provides information on both perfusion and function with a single injection. This latter technique allows differentiation between stunning and hibernating on the basis of coronary flow which is preserved in stunning and reduced in hibernation.

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